将2个JavaScript RegEx组与AND和量词结合在一起

Question

Unfortunately I try in vain to write a suitable JavaScript RegEx, which matches the following case:

1. it is matched to a singleline string, not a multiline.
2. ONLY positive if the string contains less than 6 words
3. AND if it contains any of the words "There", "This", "Dog" .

The RegEx for the 2 point is probably:

^(\\s*\\S+(?:\\s+\\S+){1,4}\\s*)$ demo

The RegEx for the 3 point is probably:

^(?=.*(There\\b|\\This\\b|\\bDog)).*$ demo

Now I have the problem to combine this 2 regex into one. I've tried something like: ^(\\s*\\S+(?:\\s+\\S+){1,5}\\s*)(?=.*(There\\b|\\bThis\\b|Dog)).*$ demo

How I can combine there 2 RegEx correctly?

Some Examples:

Hello I am under 6 words -> negative, no trigger word

Hello I am under dog words -> positive under 6 words + trigger word (dog)

Hello I am dog but with a longer string -> negative because more then 6 words

Dog -> positive, under 6 words + trigger word(dog)

Answer 1

You may put the lookahead from the second regex after ^ in the first regex and use word boundaries around the alternation:

^(?=.*\b(?:There|This|Dog)\b)\s*\S+(?:\s+\S+){1,5}\s*$

See the regex demo . Note the case insensitive modifier in the demo ( /^(?=.*\\b(?:There|This|Dog)\\b)\\s*\\S+(?:\\s+\\S+){1,5}\\s*$/i ).

It matches strings with 6 words or less that must contain There , This or Dog as whole words.

See the regex graph :